Detonator



Jan. 28, 1964 P. BEERMANN 3,119,334

DETONATOR Filed Nov. 18, 1960 20 lo b H O 2 2 IO 3 I! no I as 'Ic I 3 I3 I I I 5 1 I lb i l 6 1 l I 6 6a 1 L I a 8 8o 1 i FIG. I. FIG. 2 9 9 llu INVENTOR Paul Beermann ATTORNEY United States Patent C 3,119,334 DETUNATGR Panl Eeermann, Menden, Sanerland, Germany, assignor to Firms Richard Rinirer, Mention, Saneriand, Germany Filed Nov. 18, 196i), Ser. No. 70,353 Claims priority, application Germany Nov. 24, 1959 6 Claims. (Ci. Tim-81.6)

The present invention relates to detonators.

There exist various types of detonators, such as pressure-response and pull-type detonators. In many cases, it is desirable that the detonation be eiiected either by pressure or by a pull or trip wire, so that it was necessary to use two detonators, one of each type, side by side. If it is desirable to have the detonation take place as a result of a physical contact, yet another detonator had to be provided.

It will be appreciated that the use of multiple detonators is not only wasteful but also dangerous to the operating personnel, inasmuch as care must be taken to prevent accidental detonation of each one of the three types of detonators, lest even slight carelessness may lead to disastrous consequences.

It has been sought to overcome the above disadvantages by combining the three types of detonators into a single detonator. However, efforts in this direction have failed, partly because the resulting composite detonator was not sufficiently moisture and/ or cold resistant, thereby decreasing the reliability of the device below the acceptabie point and partly because the actuating mechanism became too complicated.

It is, therefore, an object or" the present invention to provide a detonator which overcomes the above disadvantages.

It is another object of the present invention to provide a detonator responsive to either a pulling force or to a pushing force, or to contact pressure.

The objects of the present invention also include the provision of a detonator which is reliable, which can be stored for long periods of time, which can be mass-produced at low cost, and which can be safely handled even by inexperienced personnel.

With the above objects in view, the present invention resides mainly in a detonator comprising a tubular body having at one end thereof an end wall, a detonator element arranged at the opposite end of the body, a firing pin mounted in the body for axial movement relative to the detonator element, this firing pin having a head end adapted to project through tne end wall, spring means continually urging the firing pin towards the detonator element at the opposite end of the body, and releasable retaining means for preventing movement of the firing pin under the action of the spring means. The retaining means preferably comprise a spring clip arranged exteriorly of the body and engaging a receiving groove formed in the head end of the firing pin when the head end projects through the end wall, the force of the spring means being suflicient to hold the spring clip firmly against the end wall of the tubular body, thereby sealing the one end of the body against the entry of foreign matter, while being insufiicient to move the firing pin into engagement with the detonator element against the retaining action of the clip. Additionally, a releasable safety pin is provided which passes through the head end of the firing pin, this safety pin having two parts engaging, respectively, opposite sides of the clip for preventing outward movement of the latter.

Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings, in which:

PEGURE 1 is a longitudinal sectional view of a detonator according to the present invention.

FiGURE 2 is a side view of the detonator as seen in a direction forming an angle of with the plane of FIGURE 1.

FIGURE 3 is a top plan view of the detonator.

FIGURE 4 shows a detail, on an enlarged scale, taken on the line d4l of FIGURE 2.

Referring now to the drawings, the same show a detonator having a body ll made of metal or heat-resistant plastic material which is in threaded engagement with a bottom nipple 8 having a shoulder 8a, there being a suitable sealing washer 6a interposed between the face of the body It and the shoulder 3a. The body 6 carries a striker or firing pin 1, of cylindrical or polygonal cross section, having a rounded head portion 1.1: and a safety pin 2 consisting of a part having a head 2a and a stern 2b and of another part, such as nut 11, into which the stern 2b is threaded, the nut being formed with a knurled portion lie. The head 2a of the safety pin carries a pull ring 2").

The firing pin 1 is continuously urged into the detonator, i.e., downwardly as viewed in FIGURE 1, by a compression spring 5 which is interposed between a shoulder lb of the firing pin and two washers 13 and 14 arranged at the top of the interior of the body 1. The Washers 13 and 14- are made of metal and sealing material, respectively, for preventing the entry of dirt and moisture into the interior of the body l.

The detonator further comprises a plastic sealing cap 9 containing the initiator or detonator element proper, which can be in the form of a primer or percussion cap or a delayed-action fuse 12 that can be detonated when the firing pin it is allowed to move downwardly under the influence of the spring 5.

Additionally, a wire retaining spring 10 is provided for preventing the inward movement of the firing pin 1 under the influence of the spring 5. This spring normally has the configuration best shown in FIGURE 4, namely, the retaining spring llti is in the form of a clip having two outer circular portions T3811 and two curved central portions Itiib which are spaced from each other a distance a smaller than the inner diameter b of the outer circular portions ltla, the diameter 1) being greater than the outside diameter d of the firing pin 1 and the distance a corresponding to the smallest diameter of an annular groove to of substantially semi-circular cross section, within which groove the spring portions lltib are received. The spring has a generally circular cross section, so that the cross sectional configurations of the spring and of the groove will complement each other. In this way, the thickness of the spring 14) is equal to about twice the depth of the groove 1c. If it is desired to make the thickness of the spring it more than twice the depth of the groove is, this can be done by imparting to the groove a slightly less than semi-circular cross section. As is also shown in FIGURE 4, opposite junctions lilo at which the spring portions Mia and Nb meet are spaced apart a distance 0 which is smaller than the distance a.

As best shown in FIGURE 1, the outer circular portions Ma of the retaining spring it} lie against a sealing cap 4 arranged at the top of the body 1, and the spring is held in this position by the action of the spring 5. It will be appreciated that it is the spring 10 which actually prevents the spring 5 from drawing the firing pin 1 into engagement with the primer or other detonator element 12. The purpose of the safety pin 2 is to hold the retaining spring it? in place; this result is achieved by so arranging the parts that the head 2a and the part 11 en gage the spring portions Jltib, i.e., the sides of the spring lib, as shown in FIGURE 1, thereby preventing the spring from moving out of the annular groove 10 of the firing pin 1. The pin 2 will, of course, also act as a safety de vice which positively prevents the downward movement of the firing pin into the body 6, should the retaining spring 10 inadvertently become damaged and leave the groove 10.

The configuration and strength of the spring 10 are such that even when the safety pin 2, 11, is removed, the firing pin 1 will be held in place by the spring 10, i.e., the spring 5 is not strong enough to force the retaining spring out of the groove 10 because the radial force exerted by the spring 10 will not be overcome by the radial component which the spring 5 can exert through the camming action between the firing pin 1 and the spring 10.

The detonator described above may be actuated, once the safety pin 2, 11, has been removed, by exerting a sufiicient force in the direction of the double arrow 1:3 (FIGURE 2). The force in the direction of the arrow may be exerted by a suitable trip wire attached to the outer portions 10a of the retaining spring 10, or by otherwise applying a sufiicient pulling or pushing force. As soon as one of the portions 10a of the spring 10 comes into alignment with the firing pin 1, i.e., as soon as the curved portions 10b of the spring 10 leave the groove 1c, the firing pin 1 will be free to move downwardly under the action of the spring 5.

The detonator may also be actuated by applying a sufiicient force in the direction of the arrow 16 (FIGURE 2); this may occur when a certain force, such as a weight, is brought to bear on the head end in. The force will have to be just enough to spread the central portions 16b of the spring 10 apart sufiiciently to force the spring 10 out of the groove 10, and this will free the firing pin for downward movement under the influence of the spring 5.

It will be seen from the above that a detonator according to the present invention can be activated by a pushing or pulling force, such as by a trip wire attached to one of the outer circular portions 10a of the spring clip 10, or by pressure applied in the direction of the axis of the firing pin 1. Furthermore, the arrangement of the parts is such that so long as the safety pin 2, 11, is in place, there is no danger of inadvertently detonating the device, so that the wires or the like may be safely attached to the spring clip. Also, the entire arrangement is reliable in operation, it can be mass-produced at low cost and, thanks to the sealing afforded by the interaction of the various parts, particularly by the pressure exerted on the cap 4, it is possible to store the detonator for long periods without adversely afiecting its reliability and useful life.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim: 1

1. A detonator, comprising, in combination: a tubular body having at one end thereof an end wall; an initiator arranged at the opposite end of said body; a firing pin mounted in said body for axial movement relative to said initiator, said firing pin having a head end normally projecting through said end wall, said normally projecting head end having a receiving groove; spring means continuously urging said firing pin towards said initiator at said opposite end of said body; and releasable retaining means for preventing movement of said firing pin under the action of said spring means, said retaining means comprising a flat spring clip arranged exteriorly of Said body and having two curved central portions which are received within said receiving groove of said firing pin head end and two outer circular portions each joining both of said two curved central portions and projecting laterally beyond said tubular body, the force of said spring means being sufficient to hold said spring clip firmly against the outer surface of said end wall of said tubular body, thereby sealing said one end of said body against the entry of foreign matter, while being insuflicient to move said firing pin into engagement with said initiator against the retaining action of said spring clip, the inner diameter of each of said outer circular portions being at least equal to the outside diameter of said firing pin and opposite junctions of said outer circular portions and said curved central portions being normally spaced apart a distance which is smaller than the smallest diameter of said groove, said spring clip being resiliently yieldable to permit the spacing between said last-mentioned opposite junctions to become equal to the smallest diameter of said groove, thereby allowing said spring clip .to be displaced relative to said firing pin so that the latter is ultimately encompassed by one of said outer circular portions of said spring clip.

2. A detonator as defined in claim 1 wherein said retaining means further comprise a releasable safety pin passing through said head end of said firing pin, said clip extending around said firing pin head end and said safety pin engaging said two curved central portions of said clip which are received in said groove to prevent said two central portions from spreading apart, thereby preventing withdrawal of said clip from said groove. i

3. A detonator as defined in claim 2 wherein said safety pin comprises a stem having a head at one end thereof and a nut threadable onto the free end of said stem, said head and nut engaging said curved central portions of said clip, respectively.

4. A detonator as. defined in claim 1 wherein said spring clip has a thickness greater than twice the depth of said groove.

5. A detonator as defined in claim 1 wherein said initiator is covered by a sealing cap.

6. A detonator as defined in claim 5 wherein said sealing cap is made of plastic.

References Cited in the file of this patent UNITED STATES PATENTS 1,213,397 Mills et a1. Jan. 23, 1917 1,304,544 Conrad et al May 27, 1919 1,358,652 Ragsdale Nov. 9,1920 2,100,698 Morner Nov. 30, 1937 2,512,179 Shinkle June 20, 1950 2,684,142 Willyard et al. July 20, 1954 2,717,042 Grant et a1 Sept. 6, 1955 2,853,007 Casati Sept. 23, 1958 FOREIGN PATENTS 765,026 Great Britain Jan. 2, 1957 

1. A DETONATOR, COMPRISING, IN COMBINATION: A TUBULAR BODY HAVING AT ONE END THEREOF AN END WALL; AN INITIATOR ARRANGED AT THE OPPOSITE END OF SAID BODY; A FIRING PIN MOUNTED IN SAID BODY FOR AXIAL MOVEMENT RELATIVE TO SAID INITIATOR, SAID FIRING PIN HAVING A HEAD END NORMALLY PROJECTING THROUGH SAID END WALL, SAID NORMALLY PROJECTING HEAD END HAVING A RECEIVING GROOVE; SPRING MEANS CONTINUOUSLY URGING SAID FIRING PIN TOWARDS SAID INITIATOR AT SAID OPPOSITE END OF SAID BODY; AND RELEASABLE RETAINING MEANS FOR PREVENTING MOVEMENT OF SAID FIRING PIN UNDER THE ACTION OF SAID SPRING MEANS, SAID RETAINING MEANS COMPRISING A FLAT SPRING CLIP ARRANGED EXTERIORLY OF SAID BODY AND HAVING TWO CURVED CENTRAL PORTIONS WHICH ARE RECEIVED WITHIN SAID RECEIVING GROOVE OF SAID FIRING PIN HEAD END AND TWO OUTER CIRCULAR PORTIONS EACH JOINING BOTH OF SAID TWO CURVED CENTRAL PORTIONS AND PROJECTING LATERALLY BEYOND SAID TUBULAR BODY, THE FORCE OF SAID SPRING MEANS BEING SUFFICIENT TO HOLD SAID SPRING CLIP FIRMLY AGAINST THE OUTER SURFACE OF SAID END WALL OF SAID TUBULAR BODY, THEREBY SEALING SAID ONE END OF SAID BODY AGAINST THE ENTRY OF FOREIGN MATTER, WHILE BEING INSUFFICIENT TO MOVE SAID FIRING PIN INTO ENGAGEMENT WITH SAID INITIATOR AGAINST THE RETAINING ACTION OF SAID SPRING CLIP, THE INNER DIAMETER OF EACH OF SAID OUTER CIRCULAR PORTIONS BEING AT LEAST EQUAL TO THE OUTSIDE DIAMETER OF SAID FIRING PIN AND OPPOSITE JUNCTIONS OF SAID OUTER CIRCULAR PORTIONS AND SAID CURVED CENTRAL PORTIONS BEING NORMALLY SPACED APART A DISTANCE WHICH IS SMALLER THAN THE SMALLEST DIAMETER OF SAID GROOVE, SAID SPRING CLIP BEING RESILIENTLY YIELDABLE TO PERMIT THE SPACING BETWEEN SAID LAST-MENTIONED OPPOSITE JUNCTIONS TO BECOME EQUAL TO THE SMALLEST DIAMETER OF SAID GROOVE, THEREBY ALLOWING SAID SPRING CLIP TO BE DISPLACED RELATIVE TO SAID FIRING PIN SO THAT THE LATTER IS ULTIMATELY ENCOMPASSED BY ONE OF SAID OUTER CIRCULAR PORTIONS OF SAID SPRING CLIP. 